This disclosure relates to blade tip clearance in gas turbine engines and, more particularly, to passive tip clearance control.
A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section. The compressor section typically includes low and high pressure compressors, and the turbine section includes low and high pressure turbines.
The turbine section can include a blade outer air seal system that provides a desirably minimal clearance between tips of the blades of the turbine section and surrounding shrouds around the blades. The blade out air seal system may include carrier segments that support seal segments that can, under certain operational conditions, contact the tips of the blades. In some designs, a control ring is provided in combination with the carrier segments such that the carrier segments and the control ring together determine the thermal response of the blade outer air seal system to maintain a clearance, at least under some operational conditions.